Mental Health and the Criminal Justice System

Mental health presents legal issues when crimes are committed, especially when dealing with killing or murder. Under Commonwealth law in Australia, unsoundness of mind can be used as a defence to a criminal charge. Application of this law means that people who are charged with a crime cannot enter a plea or be found guilty because of a mental disorder.Instead, they become forensic patients.

For the courts to determine mental health, expert witnesses have to attest to eligibility for the assailant to stand trial. Depending on the nature of the crime, they are released back into society with conditions, others are treated in a mental health institution. Diagnosing mental health relies on a set criteria and that criteria changes from time to time.

For example, a New South Wales study found that 48 per cent of reception inmates and 38% of sentenced had suffered a mental illness in the previous 12 months. This is when the definition of a mental disorder was limited to psychosis, affective disorder or anxiety.

When a broader definition of psychiatric disorder was used, it found that 74% of the NSW population was affected. 51% of the prisoners in Victoria reported that they had received or been assessed by a psychiatrist or doctor for an emotional or mental health problem. The numbers show that there is a higher incidence of mental health in prison than in the general population.


The standard of culpability is based on the reasonable person test, in other words, what would a regular person with intact judgment do in a similar situation. In cases where mental health is suspected, expert witness are called to ascertain if the individual has had a history of mental health or was truly suffering from mental health prior to the crime.

For the defence to determine mental health as the main reason behind the individual committing the crime, they have to prove that the person was not fully aware of what they were doing in the moments before the crime. And that social economic or environmental factors were too strong for them to exercise self-control. Invoking mental health as the defence essentially takes the responsibility away from the person who committed the crime, and puts it on the reason for why the crime was committed. There are some mental health illnesses that if a person commits a crime they should not be held accountable. For example interpretive disorders, where a person interprets reality incorrectly, or schizophrenia etc.

Another issue is, there are bad people out there, that will cause harm just for the sake of it. For example, what brings a person to the point that they go into a church, full of people minding their own business, looking at children and women in the face and opening fire? The mass shooting Vegas was even more puzzling, this was a man from the outside had everything going on for him, he did not have any criminal record and was what you call a model citizen. What got him to the point of causing death just for the sake of it.

Lastly, so if it’s not mental illness, what could cause an otherwise rational human being to take the life of another. what would cause a Mum like Susan Smith to strap her children in a car and drive to the river and watch them drown and go on national TV and lie to the world about it? Did OJ Simpson kill his ex-wife? well only he knows the truth

In a broader context, evil people have a distorted view of how to act. Evil people defy the norms of an average reasonable person.  Finding out the motive allows society to decide whether to punish the individual or treat them. Another reason we want to find out the reason for the action is, we can try to put measures in place so that it does not happen in the future. People moved on fast from the terror attack in Manhattan because we knew why the person did what he did.
The question here is after they have been treated should we as a society keep them confined or do we allow them back into society?

The law differentiates between intent and motive. The motive in criminal law is described as circumstances that induce an action. Motive in its self is not a crime, but, in criminal proceedings, knowing what motive was, is allowed to make plausible the accused reasons for committing a crime.

The intent, on the other hand, is synonymous with Mens rea, which means the mental state shows liability which enforced by law as a crime. In a criminal proceeding, the motive is not needed for a verdict. But it is taken into account when sentencing, Motive can be broken into three categories; biological, social and personal. The Judge will take into account in say abused women who kill their husbands whether the abuse they suffered affected their ability to tell right from wrong.


Intent to commit a crime means that the individual while fully aware of their actions and consequences acted to bring o the intended outcome. The problem here is that even battered women who kill are most of the times fully aware of their actions, some even plan to kill. Battered women who kill are given lighter sentences because the law takes into account societal inequality. And society has realised that people who have suffered from continued abuse will often act and behave differently, from an average person of sound mind.

The problem here is the same can be said for people who do mass shootings, Every one is a product of both genes and the environment. If for example some people are genetically or biologically predisposed to violence, does that mean that the action they take is not there fault. Because they are only dancing to whatever the DNA tells them to do? Insanity is based on the notion that the person did not have the capacity to the different right from wrong because of a defect in the brain.

In conclusion, in a study of mental health and crimes committed in Washington, only 7.5% were directly related to symptoms of mental health. The study analysed 429 crimes committed by 143 offenders with three major types of mental illness. 3% of their crimes were directly related to symptoms of depression, 4% were to symptoms of schizophrenia and 10% symptoms of bipolar disorder. The study concludes by saying “the vast majority of people with mental health issues are not violent, not criminal and dangerous” this is supported by the fact that only a few criminals who use insanity as a defence are given a lighter sentence.




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